In recent years, a lot of attention has been focused on techniques to reduce the power consumption of radio base station apparatuses. Patent literature 1 discloses a technique relating to the reduction in power requirements of a radio base station apparatus. FIG. 15 is a diagram for explaining a radio base station apparatus according to Patent literature 1. In FIG. 15, a radio base station apparatus 100 includes a control unit 120 that transmits/receive's a signal 170 to/from a network 160, and signal processing units 130_1 to 130_5 each of which transmits/receives a respective one of signals 171_1 to 171_5 to/from the control unit 120. Further, the radio base station apparatus 100 also includes a transmission/reception unit 140 that transmits/receives transmission/reception signals 172_1 to 172_5, which are transmitted to/received from these signal processing units, to/from a mobile terminal through an antenna 150. The control unit 120 controls the signal processing units 130_1 to 130_5 by transmitting/receiving respective control signals 181_1 to 181_5, and also controls the transmission/reception unit 140 by using a control signal 182. Further, the control unit 120 is connected to a terminal number estimation unit 110, and obtains the estimated number of terminals by using a signal 180.
Further, in the radio base station apparatus shown in FIG. 15, the terminal number estimation unit 110 estimates the number of mobile terminals that are present in the service area based on the number of position registrations of the mobile terminal, the number of access request messages from the mobile terminals, or the number of incoming-call notification massages to the mobile terminals. Then, the control unit 120 turns off the power supply to unnecessary signal processing units 130_1 to 130_5 based on the estimated number of mobile terminals.